Sound-reproducer.



W. LINDSAY. SOUND REPRODUCER. nPPLacMloN man nc.a\.1s\.

Patented Nov. 19, 1918.

. Way, and 3 the usua WILLIAM LINDSAY, 0F CHICAGO, ILLINOIS.

SOUND-REPROD UCER.

To all whom t may concern:

Be it known that I, WILLIAM LINDSAY, a citizen of the United States, residing at hicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Sound-Reprodueers, of which the following is a description, reference being had to the accompanying drawings, forn'xing a part of this specification, in which corresponding numerals of reference in the different figures indicate like parts.

The object of my invention is to provide a sound reproducer for use upon phonographs which, in addition to elica mess and sin plicity of construction, shall have its elements so arranged and combined as to adapt themselves to accurate adjustment in such a way as to take up all lost motion while at the same time "nsuring the maximum deli cacy, sensitivcness and freedom of action in the several movable parts, and that notwithstanding ordinary imperfections of Construc tion. `To these ends my invention consists in the combination of elements hereinafter more particularly described and definitely pointed out in the claims.

In the drawings,

Figure l indicates a face view of a reproducer ernbodyimr1 the features of my invention,

Fig. 2, an edge view thereof, n

ig. 3, is an enlarged View of a portion of said reproducer taken upon the line :iw-fl, Fig. l, viewed in the direct-1011 of the ariows there shown, a-portion being in section,

Fig. 4, is a plan view of a portion of the stylus lever and, the cross-bar by which it is supported,

Fig. 5, is grooved end 1n member,

iig. B, is a like view of said member showing a ball as it would appear when resting in the groove, and

Fig. 7, an enlarged bottom view of one of the bearing extensions or arms of the bracket. Y

Referring to the drm' ings,

a detail view in plan of the 1 indicates the casing of an ordinary reproducer, 2 the diaphragm secured in 1place in any approved stylus-lever having its long arm attached to the diaphra m at 4 and its short arm 5 provided with t e usual set-screw 6 for seeurin the stylus 7 in place. Formed upon or rigidly attached to the Stylus-lever is a fulcrum-member or cross- Inclination of Letters Patent. Application flled December 31, 1917.

of the screw controlled adjust- Patented Nov. 19, 1918. Serial No. 209,783,

bar 8, provided near its ends and preferably upon its upper face, with transverse grooves 9, 9, and upon' its lower face midway between the ends With a like groove 10, Fi 3. The grooves 9 are so formed as to cut t rough to an equal extent, a horizontal plane indicated by the dotted line 11-11, which I term the axial line or line of oscillation,` while the faced or extended in a reverse direction and to a corresponding extent past said line.

A bracket, generally designated by 12, is rigidly attached to the casing 1 by means of screws 13, said bracket servin r primarily as a pivotal su port `for the fn Crum member 8. The mi dle portion of said bracket is removed to rovide an opening for the reception of t e fulcrum bar. Inwardly extended members or portions 14, are formed upon said bracket in the ends of which are located longitudinal grooves 1b, Figs. 3 and 7. The bracket 12 beingin the plane of the axis of said arm and at intersecting angles, preferably of ninety degrees, to the notches 9 with which the parts 14 are in registration.

An ad jnsting-screw 16, is tapped into the bracket 12, and extended upwardly therein as shown in 3; said screw being secure in place by means of a lock-nut 17. The upper end of said screw is adapted to contact with the lower end of a movable member or block 18, Figs. 3, 5 and 6, which is accurately but slidably fitted into a bore in said bracket. A s line 19, attached to saidfmember and fitte to slide in a groove in the bracket, serves to prevent rotation of the member. The upper end of the adjusting member 18, has a groove 20 formed therein which forresponds *o and is in the same plane with, the gropves 15 in the parts 14,

except that it faces 1n an opposite direction.

The part 18 is in registration with the oove 10 and the groove 20 in said part is,1n the example illustrated, arranged at rightangles to the groove 10.

Balls 21, 21, hardened steel, are placed between the fulcrum member and the extensions 14, so

to lie in the grooves 9, and extend npwardly into the grooves 15` arranged at right angles thereto in the extensions 14. A like ball 422, is placed in the ygroove 2O of the adjustable member 18, su es to expreferably of bronze or.

' positely inclined faces of the grooves l5, 1n

' angles, preferably A notches,

the opposing members 14, and when it is apparent that such resultl is accomplished and it is certain that there is no play or lost motion between the counterpart memf bers and the balls, the adjustment will be complete and may be made permanent by means of the lock-'nutll` It is obvious that the opposing grooves should be placed at opposing or intersecting ri ht angles with respect t0 each other, in or er to prevent the balls from falling out. This arrangement, however, performs a more important function in that it enables the balls automatically to adjust themselves to positions and to provide for a relativey considerable degree of imperfection in u justment and construction of the parts. For example, if, in lieu 0f the opposing longitudinal and transverse sockets were formed in the opposing members to lit the balls, a failure in registration of said sockets or a slight bend ing, or warping of the stylus lever, a slight lateral misplaccmcnt in its 'connection with the diaphragm, or a warping of the fulcrum member, or inaccurate workmanship, would cause friction or binding Which would interfere with the free movement of the stylus lever and to that extent, interfere with the desired result, viz. a perfectly free movement of said. lever without any lost motion. l

inasmuch as each ball is free to roll lengthwise of each groove until it is ar-A rested by Contact with the intersecting opposi ng groove, it follows that there will be a two-point contact in each groove and that the pressure of the balls upon the fonr points will be exactly balanced. The ful crum member will, therefore be held against any lost motion while free to oscillate around said points of contact when said stylus is vibrated. It is needless to state that delicacy of adjustment in an .instrument of the kind described is of paramount importance, and the construction shown permits such adjustment to be accomplished automatically and enables the ordinary workman to obtain results equal to those of the most highly skilled mechanic.

It is obvious that the relations and adjustments of the parts mav be modified by reversal or otherwise, so long as the freebearing points are maintained in the line of the axis of oscillation. For example the longitudinal grooves may be in the fulcrum member and the transverse ones in the members 14 and 18. I do not, theref ore, Wish to be limited to either construction so long as the opposing grooves are placed at such intersecting angles with 1'e spect to each other as to maintain the balls 1n Iplace, and permit uniformity of contact.

'aving thus described my invention, I cla1m:-

1. A sound reproducer in which-is comf bined a stylus-lever having a transverse fulcrum member provided with av plurality of not less than three grooves one of which is located between the other tuo and upon the opposite side of Said fulcrum member, a stationary supporting member having counterpart grooves reversed respectively with respect to those of said fulcrum member so as to oppose the lutter und arranged at intersecting angles thereto and beul-in."ll balls located in said opposing grooves, the points of Contact between said balls and grooves forming the axis of oscillation of said fulcrurn member.

2. A reproducen, comprising, in combination, a stylus-lever having a transverse fulcrum member provided with two grooves upon one side each formed to contact with `a ball at two points only, a like groove upon the opposite side thereof substantially midway between said first named two, a stationary support having two counterpart grooves arranged at intersecting angles to those in said fulcrum member, an ad justable ball supportingr member movably mounted in said supportingI member the same having a groove in substantial regis lralion with the middle groove in said fulcrum member but arranged at an intersecting angle thereto, an adjusting screw in operative connection with said adj ustahle ball. supporting member and balls interposed between and arranged to rest in said counterpart grooves.

In testimony whereof, I have Signed this specification in the presence of two subscribing 1witnesses, this 27th day'of December, 1917.

WILLI AM LINDSAY.

Witnesses:

D-Avln H. FLETCHER JENNIE L. FIBRE. 

